Johnny Weissmuller accompanies writer Ellen Martson, archery-expert Bob Prentice and trader Mark Santo to the remote Baku area in Africa, where an ancient civilizations is rumored to have once flourished. The are captured by the pygmy Moon Men who worship the blonde high priestess Oma. Johnny agrees to become her high priest if the others are freed, but they are all condemned to death when Santo is discovered trying to steal the sacred diamonds.